The proposed work has a manifold purpose, including clarification of structural relations and of chemoarchitectonic patterns, and the development of analytical methods for accumulation of such information. Particular emphasis is placed on improved procedures for mapping interneuronal connections at the truly cellular level, with identification of pre- and post-synaptic structures in terms of the patterns of their ramifications. The Golgi method does not in its present form allow identification of submicroscopic criteria at the synapse. Methods will be searched for whereby such criteria may remain visible at the e.m. level. In an initial phase chemical identification of Golgi precipitate (four methods) has been carried out by electron and X-ray diffraction methods. Information on neurologcal systems is the ultimate goal of these attempts and our group will continue to be active in a variety of neurobiological studies. These will to a considerable extent deal with the hippocampa region, the structure and function of which need further elucidation, and which has proven an excellent model for the study of many general structural, dynamic and chemical features. Mapping of connections with silver impregnation and electron microscopy of Walerian degeneration will continue. E.m. study of normal brain made in a conventional manner will be combined with quantitative methods. High priority is presently given to the development of a computer- based method for the detailed quantitative analysis of electron micrographs. One of the final objectives of the attempts to improve Golgi methods and to develop quantitative methods is to combine these approches in a unified strategy.